object modelingにおける境界評価関数の研究

抄録

This paper reports on how to construct a solid object model on 3-dimensional modeling and how to evaluate the boundary of the defined model. The solid object model is constructed by half spaces, which is often called primitives, and with aid of a constructive operator. Two description ways are given by use of a set operator as a constructive one. The solid object modeled is mapped into 2-dimensional or 3-dimensional physical space in the form of graphic output, an auto-meshing for F. E. M., an NC-tape generation and so on. A boundary evaluator is regarded as carrying out mapping mentioned above. Boundary evaluators having been presented are discussed, then new formulations of the boundary evaluator are offered here and compared with them. An information of boundary evaluators having been presented is only a boundary (surface) of the defined model or only outer information. One of new evaluators has an outer, a boundary, and an inner informations of the defined model as a positive value, zero and a negative value, respectively. And its absolute value shows a distance to the defined model surface under some restrictions. These features are assured by plotting iso-contour lines of evaluators discussed. Furthermore, simple examples of NC-machining applied for by plotting result as a cutter path are shown. The results reached here give basic algolithm for computer-aided graphics and an NC-machining.